Posts Tagged Visual field loss

[Abstract] Functional visual fields: relationship of visual field areas to self-reported function

Abstract

Purpose

The aim of this study is to relate areas of the visual field to functional difficulties to inform the development of a binocular visual field assessment that can reflect the functional consequences of visual field loss.

Methods

Fifty-two participants with peripheral visual field loss undertook binocular assessment of visual fields using the 30-2 and 60-4 SITA Fast programs on the Humphrey Field Analyser, and mean thresholds were derived. Binocular visual acuity, contrast sensitivity and near reading performance were also determined. Self-reported overall and mobility function were assessed using the Dutch ICF Activity Inventory.

Results

Greater visual field loss (0–60°) was associated with worse self-reported function both overall (R2 = 0.50; p < 0.0001), and for mobility (R2 = 0.64; p < 0.0001). Central (0–30°) and peripheral (30–60°) visual field areas were similarly related to mobility function (R2 = 0.61, p < 0.0001 and R2 = 0.63, p < 0.0001 respectively), although the peripheral (30–60°) visual field was the best predictor of mobility self-reported function in multiple regression analyses. Superior and inferior visual field areas related similarly to mobility function (R2 = 0.56, p < 0.0001 and R2 = 0.67, p < 0.0001 respectively). The inferior field was found to be the best predictor of mobility function in multiple regression analysis.

Conclusion

Mean threshold of the binocular visual field to 60° eccentricity is a good predictor of self-reported function overall, and particularly of mobility function. Both the central (0–30°) and peripheral (30–60°) mean threshold are good predictors of self-reported function, but the peripheral (30–0°) field is a slightly better predictor of mobility function, and should not be ignored when considering functional consequences of field loss. The inferior visual field is a slightly stronger predictor of perceived overall and mobility function than the superior field.

Source: Functional visual fields: relationship of visual field areas to self-reported function – Subhi – 2017 – Ophthalmic and Physiological Optics – Wiley Online Library

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[WEB SITE] Visual effects and rehabilitation after stroke

Fiona Rowe. Reader in Orthoptics and Health Services Research, Hon Professor of Orthoptics UTS, University of Liverpool, UK.http://www.liverpool.ac.uk/psychology-health-and-society/research/vision/about

Strokes, or cerebrovascular accidents (CVA) are common, particularly in older people. The problems of motor function and speech are well known. This article explains the common visual problems which can occur with a stroke and gives information about diagnosis and management.

What is a stroke?

A stroke occurs when there is an interruption to blood flow to the brain either because of a blood clot blocking the blood vessel or a haemorrhage in the brain.1 Strokes can cause signs which are obvious, such as loss of speech, drooping of one side of their face, or weakness or paralysis of the arm and/or leg on one side of the body.1 The vision is affected in about two thirds of people who have had a stroke, but this is often not obvious to the patient or their carers. For example, someone who has weakness down one side may bump into things or not eat all the food on their plate, not realising that this may also be because they have visual field loss.2

What causes a stroke?

A stroke or cerebrovascular accident, (CVA) is the result of a blocked blood vessel in the brain (thrombosis or embolus), or haemorrhage into the brain.1 Strokes are more likely in the elderly, and those who have high blood pressure, diabetes or cardiovascular disease.

Types of visual loss in people who have had a stroke

There are four ways in which vision can be affected following a stroke:

  1. Loss of central vision
  2. Visual field loss
  3. Visual perceptual abnormalities
  4. Eye movement abnormalities

These may occur in isolation but more frequently occur in combination.3 Problems with central vision are quite common after a stroke. The symptoms include blurred or altered vision. In many the vision improves, but the visual loss can be permanent.

Visual field loss occurs in up to half of people with a stroke, with the commonest defect being homonymous hemianopia in which vision is lost in the right or the left visual fields (Figure 1).4 Patients may not be aware of this, and bump into door frames or trip over things on the affected side. Reading can also be difficult (Figure 2).

Image showing loss of field of vision in both eyes
Figure 1. Right homonymous hemianopia: the right-hand field of view is lost in both eyes
Image illustrating how a page of text appears to someone with double vision and someone with right hemianopia
Figure 2. Impact of vertical double vision (central image) and right hemianopia (right image) on reading

Visual perceptual deficits are many and varied affecting about a third of people with a stroke. Problems that may develop include neglect one side of their body; difficulty recognising faces or objects, or difficulties with colour vision, depth perception and motion.5 Eye movement abnormalities can also be varied, including strabismus (misaligned eyes), difficulty in converging the eyes to look at near objects, or double vision due to the cranial nerves which control eye movement being affected.6 Typical symptoms include double vision, or jumbled, blurred and/or juddery vision (Figure 2).

Impact

Blurred vision, double vision and lossand loss of visual field are significant symptoms that impair daily functioning.7 The patient or their close relatives may report that they frequently bump into objects such as door frames; have difficulty finding things on surfaces; are unsure of their footing while walking and stumble; may leave food uneaten on one side of the plate and have difficulty with reading. Other impacts on the quality of life include loss of confidence, fear of falling, fear of going out alone, social isolation and loss of independence.8

How to assess visual function in someone who has had a stroke

Examination for visual loss is essential for stroke survivors.9 There are various assessment tools which can be used to examine visual function after a stroke:

Management

Treatment options aim to restore visual function to as normal as possible.10 For eye movement abnormalities,prisms and patching one eye can be effective in reducing double vision.6 For visual field loss a Cochrane systematic review reports favourable evidence of visual scanning training which aims to compensate for the visual field loss.11 It is available as a paper training option (www.strokevision.org.uk) or through computer training (www.eyesearch.ucl.ac.uk; www.readright.ucl.ac.uk.

Stroke survivors with persistent impairment of central vision may be helped by low vision services which can include magnifiers, reading aids, computerised adaptations and improved lighting.12 Furthermore, simple adaptations can be made by stroke survivors such as using large print, ensuring good lighting at home, putting labels or coloured stickers on cooking equipment, decluttering areas and having a companion when going out, particularly in busy, crowded places.10

Conclusion

Post-stroke difficulties in visual function are an under-recognised problem that cause significant impact to the quality of life of stroke survivors. Carers and health workers need to be aware that problems with vision are a common consequence of stroke that is not outwardly obvious. Assessment including visual functioning is best provided as part of a multi-disciplinary team on acute stroke units, or in neuro-rehabilitation units. A careful history about visual problems from the patient and carers followed by examination of visual acuity, eye movements and visual field are important in understanding the difficulties in visual functioning.

Management should be tailored to each individual, their visual difficulties and visual needs. With about one quarter of stroke survivors being of working age, rehabilitation in the conext of adaptation of the work place environment is vital if younger people are to return to work after stroke. Rehabilitation requires patience and perseverance on the side of the client, relatives and the health provider.

Despite improvement in stroke prevention and acute stroke management, the increasing ageing population will result in more stroke survivors requiring rehabilitation. Policy makers need to understand the importance of providing post-stroke rehabilitation services including visual functioning.

References

All webpages accessed 30th January 2017

1 World Health Organization. Stroke and cerebrovascular accident. 2017. http://www.who.int/topics/cerebrovascular_accident/en/

2 Hepworth LR, Rowe FJ, Walker MF, Rockliffe J, Noonan C, Howard C, Currie J. Post-stroke Visual Impairment: A Systematic Literature Review of Types and Recovery of Visual Conditions. Ophthalmology Research: An International Journal. 2015; 5(1). ISSN: 2321-7227

3 Rowe FJ, VIS group. Visual impairment following stroke. Do stroke patients require vision assessment? Age and Ageing. 2009; 38: 188-193

4 Rowe FJ, VIS UK. A Prospective Profile of Visual Field Loss following Stroke: Prevalence, Type, Rehabilitation, and Outcome. BioMed Research International, vol. 2013, Article ID 719096, 1-12, 2013. doi:10.1155/2013/719096.

5 Rowe FJ, VIS group. Visual perceptual consequences of stroke. Strabismus 2009; 17: 24-28

6 Rowe FJ, VIS group. The profile of strabismus in stroke survivors. Eye 2010; 24: 682-5

7 Rowe FJ, VIS Group. Symptoms of stroke related visual impairment. Strabismus, 2013; 21: 150-4

8 Hepworth L, Rowe FJ. Visual impairment following stroke – the impact on quality of life: a systematic review. Ophthalmology Research: an international journal. 2016; 5(2): 1-15

9 Rowe FJ. The importance of accurate visual assessment after stroke: Editorial. Expert Reviews in Ophthalmology. 2011: 6; 133-6

10 Rowe FJ. Care provision and unmet need for post stroke visual impairment; Final report. 2013. http://www.stroke.org.uk/sites/ default/files/final_report_unmet_need_2013.pdf?

11 Pollock A, Hazelton C, Henderson CA, Angilley J, Dhillon B, Langhorne P, Livingstone K, Munro FA, Orr H, Rowe FJ, Shahani U. Interventions for visual field defects in patients with stroke. Cochrane Database of Systematic Reviews 2011, Issue 10. Art. No.: CD008388. DOI: 10.1002/14651858.CD008388.pub2.

12 Virgili G, Rubin G. Orientation and mobility training for adults with low vision. Cochrane Database of Systematic Reviews 2010, Issue 5. Art. No.: CD003925. DOI: 10.1002/14651858.CD003925.pub3

Source: Community Eye Health Journal » Visual effects and rehabilitation after stroke

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[Abstract] Homonymous Hemianopia and Vision Restoration Therapy

Homonymous hemianopia from stroke causes visual disability. Although some patients experience spontaneous improvement, others have limited to no change and may be left with a severe disability. Current rehabilitation strategies are compensatory and cannot restore function. Animal studies suggest that central nervous system plasticity could allow for redirection of lost visual function into undamaged areas of cortex. A commercial therapy system was developed, from which claims of visual field expansion were disputed by independent researchers. The treatment remains controversial with seemingly contradictory data being generated. Continued research is underway to demonstrate the (non-)efficacy of this treatment method.

Source: Homonymous Hemianopia and Vision Restoration Therapy – Neurologic Clinics

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[WEB SITE] Decreased vision on the left side leads to hemianopia diagnosis

Damage from stroke years ago prompts field loss today

April 22, 2015 By Madeline Bost, Christopher J. Borgman OD FAAO

A 39-year-old African-American female presented to The Eye Center at Southern College of Optometry with complaints of blurred vision, loss of side vision to the left, and trouble with mobility. She was diagnosed with hypertension, hypercholesterolemia, and type II diabetes mellitus in 2007 when she was admitted to the hospital for a stroke. The stroke left her with left-side weakness, and she occasionally suffered seizures. More recently, she had also reported being diagnosed with systemic lupus erythematosus. Her family ocular history was unremarkable—her paternal grandmother had diabetes, and her mother had hypertension. She smoked several times a week and reported no alcohol or recreational drug use. Her medications included prednisone, levetiracetum (Keppra, UCB), amitriptyline (Elavil, AstraZeneca), metformin, and simvastatin (Zocor, Merck). She reported an allergy to sulfa antibiotics. Blood pressure was measured manually in-office at 111/76 mm Hg.

Case presentation

Entering visual acuities were 20/70 OD and 20/400 OS, which improved with pinhole to 20/30 OD and 20/50 OS. Confrontation visual fields were restricted nasally OD and restricted in all gazes OS. Extraocular motilities were full in all gazes; cover test showed orthophoria at distance and near; and pupils were equal, round, reactive to light and accommodation with a positive afferent pupillary defect (APD) OS. Goldmann applanation tonometry was 19 mm Hg OD and 20 mm Hg OS. A new subjective refraction improved vision to a slow 20/20 in OU. Biomicroscopy was unremarkable OU. Examination of the posterior segment showed optic nerve pallor, more severe temporally OS compared to OD (see Figures 1 and 2). There was also lattice degeneration in the periphery OU but no signs of retinal breaks present. No diabetic retinopathy was noted OU.

Continue —>  Decreased vision on the left side leads to hemianopia diagnosis | OptometryTimes.

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[WEB SITE] Introduction to Vision & Brain Injury

Vision is our dominant sense

More than just sight is measured in terms of visual acuity, vision is the process of deriving meaning from what is seen. It is a complex, learned and developed set of functions that involve a multitude of skills. Research estimates that eighty to eighty five percent of our perception, learning, cognition and activities are mediated through vision.

The ultimate purpose of the visual process is to arrive at an appropriate motor, and/or cognitive response.

There is an extremely high incidence (greater than 50%) of visual and visual-cognitive disorders in neurologically impaired patients (traumatic brain injury, cerebral vascular accidents, multiple sclerosis etc.) Rosalind Gianutsos, Ph.D.

“Visual-perceptual dysfunction is one of the most common devastating residual impairments of head injury”. Barbara Zoltan, M.A., O.T.R.

“The majority of individuals that recover from a traumatic brain injury will have binocular function difficulties in the form of strabismus, phoria, oculomotor dysfunction, convergence and accommodative abnormalities”. William Padula, O.D.

Continue —>  Introduction to Vision & Brain Injury.

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[ARTICLE] Should Visual Restoration Therapy be Used in Patients With Visual Field Loss?

 

Should Visual Restoration Therapy be Used in Patients With V… : Journal of Neuro-Ophthalmology.

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[ARTICLE] A computerized perimeter for assessing modality-specific visual field loss – Full Text PDF

Abstract

The characterization of visual field loss provides a
valuable diagnostic metric for studying the effects of damage to
the retina, optic nerve or visual cortex. We describe a tool, the
Quadrant Vision Perimeter (QVp), to rapidly and accurately
measure visual fields. In addition to measuring the location of
visual deficits, the tool can assess modality-specific field loss
(e.g., impaired detection of luminance, motion, depth and color)
and severity of the deficit. We present validation and
normalization for parameters of visual attributes, as well as
exemplar comparisons of visual fields obtained automatically
using QVp to standardized perimeters for three stroke patients.
Patient visual fields are compared among visual features to
assess modality-specific deficits, and over time, to measure fine
changes in visual fields, due either to spontaneous recovery or
visual degradation.

Full Text PDF

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